I am looking to purchase a new Mac Pro. There are processor options that are driven mostly by what applications you are running. It suggests that apps that do not take advantage of multi-threading will run best on processors with higher clock speeds while those that do will benefit from more cores. Will Lightroom perform better with more cores or a higher clock speed?
Lightroom does take advantage of multiple threads as well as saturates the CPU at times, but a lot of time there is some other bottleneck on the system like I/O to the disks or video memory so the gains of either thread or cpu optimization are muted.